A simple lateral flow biosensor for the rapid detection of copper(ii) ions based on click chemistry

Abstract

Copper(II) ions (Cu²⁺) at a high concentration are harmful to human health. Herein a simple and enzyme-free lateral flow biosensor for the rapid detection of Cu²⁺ based on copper(I) ion (Cu⁺)-catalyzed click chemistry has been constructed for the first time. In the presence of sodium ascorbate, Cu²⁺ was reduced to Cu⁺, which could catalyze the cycloaddition between azide-DNA and alkyne/biotin-DNA in aqueous solution. The ligated DNA product could then be immobilized onto the test zone of the lateral flow biosensor to form a red band which could be unambiguously read by the naked eye. Taking advantage of the optical properties of gold nanoparticles (AuNPs) and high efficiency and selectivity of Cu⁺-catalyzed click chemistry, this assay enabled the visual detection of Cu²⁺ as low as 100 nM with excellent specificity. In comparison with conventional methods, this biosensor is more simple to operate and more cost-effective to use, and therefore has great potential in point-of-care diagnosis and environmental monitoring.